The first-year general manager had to strike quickly to find an experienced No. 2. The Bears invested big money in Jason Campbell, signing him to a one-year, $3.5 million deal at the outset of free agent.

Campbell making the 71st start of his career Monday night at Candlestick Park was nowhere near as good as Kaepernick making his first start. The 2011 second-round pick from Nevada led a destruction of the Bears defense as the 49ers won a 32-7 rout.

The Bears managed just 143 yards offense, their worst output since the 2010 game at the Giants when Jay Cutler was sacked nine times in the first half and concussed. Linebacker Aldon Smith of the 49ers had 51/2 sacks, a record versus the Bears.

"Tonight was probably the worst nightmare," Campbell said. "Our goals and everything are still set ahead of us, but we've got to start improving and improving quickly. The games don't get any easier."

The Bears must wonder if Cutler will be able to return from his latest concussion in time for Sunday's game against the Vikings at Soldier Field and coach Lovie Smith was optimistic afterward. Smith will have to contemplate what happened to his defense, which got mauled by the 49ers. The absence of Cutler had nothing to do with the Bears surrendering a 96-yard touchdown drive in just four minutes as San Francisco (7-2-1) jetted to a 20-0 lead.

All signs pointed to Alex Smith starting for the 49ers after he suffered a concussion a week ago, but news broke Monday morning that he had not passed his neurological exam. So Kaepernick was thrust into a starting role after Smith got much of the work in practice last week. Known for his running ability, Kaepernick carved up the secondary from the start to catch the Bears — in particular safeties Major Wright and Chris Conte — off guard.

Kaepernick completed 16 of 23 passes for 243 yards and touchdown passes to Vernon Davis and Michael Crabtree. He may have created a quarterback controversy in the Bay Area, where Alex Smith always has seemed to be on shaky ground. Coach Jim Harbaugh did little to quiet a brewing controversy afterward, saying, "We'll see. Usually tend to go with the guy who's got the hot hand."

Having lost two straight, the Bears (7-3) are in a tie with the Packers (7-3) atop the NFC North, but Green Bay won the Week 2 meeting. It sets up to be an interesting finish with the Vikings (6-4) only a game back. The Bears host the Packers on Dec. 16 in a game that could decide the division.

But the Bears cannot be thinking about the postseason after being worked over. The offense ended a drought of 111 minutes, 37 seconds without a touchdown when Campbell connected with Brandon Marshall for a 13-yard touchdown late in the third quarter. Lovie Smith's formula for takeaways was not successful as the Bears came up empty for the first time this season.

"It was embarrassing," center Roberto Garza said. "We're a much better team than that. This is not the type of team we are. We have to find out what is going on."

The run defense was vulnerable again as Frank Gore carried 17 times for 78 yards and backup Kendall Hunter gained 27 yards and scored on a 14-yard carry. This on the heels of consecutive 100-yard games by the Texans' Arian Foster and Titans' Chris Johnson with Vikings star Adrian Peterson set to face the Bears for the first time this season Sunday.

"You've got to admit they gave it to us," defensive end Corey Wootton said. "We got our butts kicked."

Meanwhile, the Bears failed in effort to get their ground game going. Matt Forte gained 63 yards on 21 carries and Michael Bush was ineffective. Campbell was under siege even before the score got out of hand. He completed 14 of 22 passes for 107 yards and was intercepted twice. He was sacked six times as outside linebacker Aldon Smith dominated tackles J'Marcus Webb and Gabe Carimi. The 49ers did a nice job covering Brandon Marshall as he was limited to two receptions for 21 yards.

If the previous two games have proved anything, it's that the first half of the schedule was packed with cupcakes. Emery has been out on the road scouting in advance of a big predraft meeting next month. He probably didn't need to see this wreck to know offensive linemen, plural, must be a priority even over a backup quarterback.